This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-020133, filed Jan. 28, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a novel poly(porphyrin) and a method of producing the same. The poly(porphyrin) of the present invention may be used as a device for conducting photonic energy and electronic energy.
It has been expected that porphyrin is used as a device for conducting photonic energy and electronic energy by using a conjugated xcfx80 electron system. For example, Lindsey et al. have reported a porphyrin polymer (J. Am. Chem. Soc., 118, 3996 (1996)) in which porphyrin units are formed into an array by connecting with a covalent bond. Fuhrhop et al. have reported a linear polymer synthesis (degree of polymerization: 200) by polymerizing porphyrin metal complex units through an electrolytic polymerization reaction (J. Am Chem. Soc., 121, 6664 (1999)).
However, these poly(porphyrin)s are produced by connecting porphyrin monomers with covalent bonds. Once porphyrin units are formed into a poly(porphyrin) array through the covalent bonds, it becomes difficult to flexibly make up and break down the array. Therefore, the application range of the poly(porphyrin) as a photonic or electronic energy-conducting device may be limited.
An object of the present invention is to provide a poly(porphyrin) constructed by porphyrin units, which is easily cleaved or reconstructed, and also provide a method of producing the poly(porphyrin).
The present inventors found that, the coordinate bonds of an imidazolyl porphyrin metal complex dimer, which is formed between a core metal of one monomer to an imidazolyl group of the other monomer are easily cleaved in the presence of a polar solvent such as methanol, even though the binding force of the coordinate bond is quite strong. The present invention was accomplished based on the finding.
The present invention provides a poly(porphyrin) constructed by imidazolyl porphyrin metal complex units, and is represented by the following general formula (I): 
where M is a metal ion selected from the group consisting of Zn, Ga, Ru, Fe and Co; R1 is a group selected from the group consisting of an alkyl group, unsubstituted aryl group, alkyl-substituted aryl group, and alkyloxy-substituted aryl group; Im is an imidazolyl group represented by Im1 or Im2 set forth below: 
where R2 represents a hydrogen atom or a methyl group; and
n is an integer of 1 or more; provided that the central metal ion represented by M may be coordinated or not coordinated to at least one of the porphyrin rings positioned at both ends of the general formula (I).
More specifically, in the general formula (I), the alkyl group represented by R1 is an alkyl group having 1-20 carbon atoms. The unsubstituted aryl group represented by R1 is an aryl group having 6-14 carbon atoms. The alkyl-substituted aryl group represented by R1 is an aryl group having 6-14 carbon atoms with at least one alkyl group having 1-18 carbon atoms as a substituent(s). The alkyloxy-substituted aryl group represented by R1 is an aryl group having 6-14 carbon atoms with at least one alkyloxy group having 1-18 carbon atoms as a substituent(s).
Much more specifically, the present invention provides a poly(porphyrin) represented by the formula (I), where M is a zinc ion, R1 is an alkyl group, and Im is Im1 where R2 is a methyl group.
The present invention also provides a method of producing a poly(porphyrin) represented by the general formula (I) mentioned above. The method comprises the steps of:
(a) inserting the metal ion represented by M into a porphyrin monomer represented by a general formula (I) set forth below, as a central metal ion, thereby producing a complementarily coordinated dimer represented by a general formula (III) set forth below: 
where M, R1, and Im are as defined above in the general formula (I);
(b) performing a coupling reaction at meso-position of the complementary coordinated dimer of the general formula (III) obtained in the step (a) and removing the central metal ion from them, thereby producing a meso-meso dimer represented by a general formula (IV): 
where R1 and Im are as defined above in the general formula (I); and
(c) inserting a central metal ion represented by M into the meso-meso dimer of the general formula (IV) obtained in the step (b), thereby coordinating the central metal ion M to Im to produce the poly(porphyrin) represented by the general formula (I).
More specifically, the above step (c) is performed in a solvent where the polarity thereof is controlled.
The present invention is also directed to the step (c) mentioned above, i.e., the present invention provides a method of producing a poly(porphyrin) represented by the general formula (I), comprising a step of inserting the metal ion M into the meso-meso dimer represented by the general formula (IV) in a solvent where the polarity thereof is controlled, wherein R1, Im, R2 and n are as defined above for the general formula (I).
In one aspect of the method of producing a poly(porphyrin) represented by the general formula (I) from the meso-meso dimer represented by general formula (IV), when a mole ratio of the metal ion M to the meso-meso dimer is set at a value less than 2, the thus produced poly(porphyrin) does not have the metal ion represented by M in the porphyrin rings at both ends thereof.
The present invention also provides a method of producing a poly(porphyrin) represented by the general formula (I), comprising a step of adding a predetermined amount of a polar solvent into a solvent of a poly(porphyrin) represented by the general formula (I). The thus produced poly(porphyrin) has the metal ions represented by M in the porphyrin rings at both ends thereof. The number represented by n of the thus produced poly(porphyrin) becomes smaller than that of the starting poly(porphyrin).
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.